Carburetor

ABSTRACT

A carburetor assembly has primary and secondary venturi passages to supply a lean mixture to main combustion chambers of an engine, and has an auxiliary venturi passage to supply a rich mixture to auxiliary combustion chambers of the engine. A throttle valve in each passage is provided with a shaft, and the shaft for the primary throttle valve projects through a hollow hub on the carburetor body. Several members and springs are mounted on the hub and serve to control turning movement of all throttle shafts during various operating conditions of the engine. A link is pivotally connected at one end to an arm which turns with the primary throttle valve and is pivotally connected at the other end to an arm which turns with the auxiliary throttle valve. An angular adjustment is provided between the auxiliary throttle valve and its respective arm. The geometric relationships of the link and arms are such as to provide the desired coordinated movement between the throttle valves.

Dec.

3,570,821 3 1971 Walker............... HIM/23A CARBURETOR [75]Inventors: Toshimasa Shishido, Tokyo; Minoru n o y .L d n Sou k1 11m M..L mm H r u .m[ in H8 i 5 e mm mm. f. PA n a. wnm a f 0M 3 m a 0WD- W"5K a eek a i a mMh nk $.03 AHK me e n .w S S A U 7 ABSTRACT July 30,1973 [22] Filed:

A carburetor assembly has primary and secondary venturi passages tosupply a lean mixture to main Appl. No.:

combustion chambers of an engine, and has an auxiliary venturi passageto supply a rich mixture to auxiliary combustion chambers of the engine.A throttle valve in each passage is provided. with a shaft, and theshaft for the primary throttle valve projects through a hollow hub onthe carburetor body. Several members and springs are mounted on the huband serve to con yGIA MG m m r m n2 a m y W D 2G S m W2 6m B7. n an 5H mmm m m r 5 .w U hF i i] 2 18 5 55 i [rt [56] References Ci d trolturning movement of all throttle shafts during various operatingconditions of the en gine. A link is piv otally connected at one end toan arm which turns with the primary throttle valve and is pivot-allycoir nected at the other end to an arm which turns with the auxiliarythrottle valve. An angullar adjustment is provided between the auxiliarythrottle valve and its respective arm. The geometric relationships ofthe link 7 WAAA 333 222 3///3 /l 2 666 222. S M." T H mm N W mm E m..mmM mmmmm P I I H Wmm Mm r .r T we m m Am d nfla T acf SMWCRB D B82792T35556 l99999 N U 0 632. 20052 1 984 209 2 22223 Edclbrock, Jr. l23/l27and arms are such as to provide the desired coordinated movement betweenthe throttle valves.

Baer...............

Karlovitz....

3,439,658 Simonct.........,..

Bartholomew................1... 261/23 A 23 Claims, 15 Drawing FiguresPATENTEL E55 974 SIEEI 2 BF 5 PATENHQL BEE 31974 MEN 5 0f 5 I]CARBURETOR This invention relates to internal combustion sparkignitionpiston engines in which each cylinder is provided with a main combustionchamber and an auxiliary combustion chamber connected by a torch nozzle.An engine of this type is disclosed in the copending application of Dateet a1. Ser. No. 353,786 filed Apr. 23, 1973 and entitled Reduction of NHC, and CO in the Exhaust Gases of Internal Combustion Engines.

More specifically, this invention relates to a carburetor assembly forsupplying a lean mixture to the main combustion chambers and a richmixture to the auxiliary combustion chambers. It is important that theairfuel ratios of the lean mixture and the rich mixture be maintainedwithin close limits for all operating conditions of the engine, in orderto avoid the production of unwanted pollutants in the exhaust gases ofthe engine. Thus, it is important to minimize production of pollutantsduring cranking, fast idling, slow idling, accelera tion, gear shifting,highway operation, slow deceleration, and rapid deceleration.

In accordance with this invention, the shaft for one of the throttlevalves, preferably the primary throttle valve, projects through astationary hollow hub formed integrally on the carburetor body. Anactuator member is mounted to turn on the hub against the action of aspring, and the throttle cable is connected to the actuator member. Aconnector member fixed to the projecting end of the shaft connects theactuator member to the shaft. In this way, the tension in the throttlecable is resisted by the hollow stationary hub, and the tension does notresult in bending of the throttle shaft. Other members affectingormodifying the turning movement of the throttle shaft are also mounted onthe hollow stationary hub, and the lateral forces which they produce arealso absorbed by the hub, and not by the throttle shaft. These featureshelp to insure smooth opening and closing of the throttle valve.

Also, a novel controlling of connection is established between theprimary throttle valve connecting the lean mixture and the auxiliarythrottle valve controlling the rich mixture. This connection isaccomplished without the use of cams, and very accurately regulates theposition of the auxiliary throttle valve for each angular position ofthe primary throttle valve. This connection employs a link pivotallyconnected to a forward extending arm on one throttle shaft and pivotallyconnected to a rearward extending arm on the other throttle shaft,

together with an adjustment device for varying the angular position ofone of the arms with respect to its re spective throttle shaft. In thisway the linkage and adjustment device helps to insure that the properamount of rich air-fuel mixture is supplied to the auxiliary combustionchambers of the engine, in relation to the amount of lean air-fuelmixture supplied to the main combustion chambers of the engine, underany oeprating condition of the engine. Also, a novel form of mechanismis employed for causing opening of the secondary throttle valve afterthe primary throttle valve has openeda predetermined amount, togetherwith positive means for closing the secondary throttle valve as theprimary throttle valve moves toward closed position. Vacuum-operatedmeans are employed for positioning certain of the throttle valves duringcertain of the operating conditions of the engine. Additional means areprovided for preventing too rapid closure of certain throttle valves andfor insuring rapid closing of the throttle valves when the electricalignition system is de-energized.

Other and more detailed objects and advantages will appear hereinafter.In the drawings:

FIG. 1 is a side elevation partly broken away showing a preferredembodiment of our invention.

FIG. 2 is a sectional elevation taken substantially on the lines 2-2 asshown in FIG. 1.

FIG. 3 is a bottom plan view showing a portion of the apparatus.

FIG. 4 is a top plan view of the same portion of the apparatus.

FIG. 5 is a side elevation,,certain parts being omitted for clarity ofillustration and showing the primary throttle valve in closed position.

FIG. 6 is a view similar to FIG. 5 showing the primary throttle valve inopen position.

FIG. 7, 8 and 9 are side elevations showing details of the cam andfollower connection between the primary throttle valve and the secondarythrottle valve.

FIG. 10 is a plan view showing a modification.

FIG. 11 is a side elevation of the device shown in FIG. 10.

FIG. 12 is a plan view of a portion of FIG. 10, certain parts beingomitted.

FIG. 13 is a sectional detail taken substantially on lines 13l3 as shownon FIG. 10,

FIG. 14 is a side elevation showing a second modification.

FIG. 15 is a sectional detail taken substantially on the line l5l5 asshown in FIG. 14.

Referring to the drawings, a carburetor assembly generally designated10includes a metal body 11 having walls defining a primary passage12, asecondary passage 13 and an auxiliary passage 14. These passages areparallel and each is provided with a venturi throat 15, 16 and 17,respectively Fuel jets fed from float chambers within the body 11produce a lean mixture in the passages 12 and 13 to supply the maincombustion chambers of the engine and produce a rich mixture in thepassage 14 to supply the auxiliary combustion chambers of the engineEach of the passages 12, 13 and 14 is provided with a throttle valvecarried on a shaft which turns relative to the carburetor body 11. Thus,the primary throttle valve 18 is fixed on the shaft 19, secondarythrottle valve 20 is fixedon the shaft 21, and auxiliary throttle valve22 is fixed on the shaft 23. The shafts 19, 21 and 23 are parallel.

As best shown in FIG. 2, a tubular part is cast into a wall of thecarburetor body 11 and projects outward therefrom to form a hollow hub24 encircling a portion of the throttle shaft 19. An actuatormember'generally designated 25 is mounted to turn on the stationary hub24, and this member 25 is constructed of two metal stampings 26 and 27fixed together by a pin 28 to turn as a single integral unitQThisunitary member 25 is acted on by a torsion spring 29 which encircles thehub 24 whichhasone end engaging the stop pin 30 and the other end 31engaging the unitary member 25. The torsion spring 29 thus acts on theunitary member 25 to turn it in .a clockwisedirection as viewed in FIG.1, opposing opening movement of the primary throttle valve 18.

The part 26 of theunitary member 25 includes an axially extending fin 33which has a portion thereof received within slot 34 on the Connectingmember 35.

The connecting member 35 is fixed to a projecting end portion of theshaft 19 by means of the nut 36. From this description it will beunderstood that the unitary member is mounted on the stationary hollowhub 24 but is connected to turn with the throttle shaft 19.

The part 27 of the unitary member 25 carries an integral socket 37 whichreceives a terminal fitting 38 at the end of'the throttle cable 39. Thiscable 39 passes through an enclosing tube 40 fixed to the stationarybracket 41 by means of lock nuts 42. Tension applied to the throttlecable 39 acts on the unitary member 25 to turn it in a clockwisedirection as viewed in FIG. 1, against the action of the torsion spring29. This turning movement of the member 25 causes the connecting member35 to turn the throttle shaft 19 in a direction to open the primarythrottle valve 18 in the passage 12. The closed position of the throttlevalve 18 is determined by the setting of the adjusting screw 43 whichengages the stop finger 44 provided on the part 27. Opening movement ofthe throttle valve 18 is limited by contact of the stop finger 45 withthe stationary stop pin 30.

The linear force applied by the throttle cable 39 to the socket 37 doesnot place a bending loadon the throttle shaft 19 because the actuatormember 25 is mounted on the stationary hub 24 and not on the shaft 19.The torque on the member 25 is transmitted to .the throttle shaft 19through the connecting member 35.

Two other members are mounted to turn on the hollow hub 24. One ofthese, the throttle positioner 47, has an arm 48 pivotally connected toan actuator rod 49 extending from the vacuum-operated diaphragm assembly50. Another arm on the throttle positioner'47 has a rounded nose portion51 engaging a side face of the fin 33. The slot 52 is provided forinitial factory adjustment ofthe rounded nose 51 with respect to the fin33, by inserting a deforming tool into the slot. The other member,mounted to turn on the hollow hub 24, is identified by the numeral 53,and this member has a first arm 54 pivotally connected at 55 to theactuator rod 56 extending .from the diaphragm assembly 57. A roundednose portion 58 on the arm 54 contacts the shoulder 59 on the part 27 ofthe unitary member 25.

, The slot provides a means for factory adjustment of the position ofthe rounded nose 58.

The part 27 of the unitary member 25 has an external cam surface 62which cooperates with the follower roller 63 on the member 64. Thismember turns with the shaft 21 for the secondary throttle valve 20. Theshaft 21 projects through the hollow stationary hub 65 and itsprojecting end is fixed to the member 64. Another member 66' is mountedto turn on the stationary hub 65 and is provided with'a radialprojection 67 which is engaged by one end 68 of a torsion spring 69. Theother end 70 of the torsion spring engages a stationary projection 71 onthe carburetor body 11. From this description it will be understood thatthe torsion spring 69 acts to turn the member 66 in a clockwisedirection as viewed in FIG. 1. The projection 67 on the member 66applies a force to the finger 72 of the member 64 in a directionopposing opening movement of the secondary throttle valve 20. A roller72a mounted on the unitary member 25 engages the cam surface 73 on amember 66 after the primary throttle shaft 19 has passed through apredetermined arc of travel in an opening direction. Further turningmovement of the unitary member 25 in an opening direction causes theroller 72a to move the member 66 in a counterclockwise direction againstthe action of the torsion spring 69.

Prior to engagement of the roller 72a with the cam surface 73, the camsurface 62 is moved with respect to the roller 63 to a position whereinthe member 64 may turn in a counterclockwise direction. Turning movementof the secondary throttleshaft 21 is accomplished by means of thevacuum-operated diaphragm assembly 75 acting through rod 76 and pivotalconnection 77 with-the member 64.

Means are provided for coordinating the movement of the primary throttlevalve 18 and the auxiliary throttle valve 22. It is essential that thesetwo throttle valves be accurately controlled during-all operatingconditions of the engine, in order to minimize unwanted pollutants inthe exhaust gases of the engine. A link 78 is pivotally connected at 79to a forward extending arm 80 carried on the actuator member 25. Thelink 78 is pivotally connected at 81 to the rearward extending arm 82 onthe member 83 which turns about the axis of the throttle shaft 23.Another member 84 which is fixed to the throttle shaft 23 is adjustableconnected to the member 83 by means of the adjusting screw 85. Theadjusting screw controls the relative angular positions of the members83 and 84, and in this way controls the relative positions of the pivot81 with respect to the auxiliary throttle valve 22. A tension spring 86extends between the pivots 79 and 81 to take up any looseness.

The throttle valves 18 and 22 are shown in closed position in FIG. 5 andin open position in FIG. 6. In order to obtain the desired angularmovement of the auxiliary throttle valve 22, with respect to the primarythrottle valve 18, the effective length a of the short arm 80 should beabout 3/4 of the effective length [2 of the long arm 82, as shown inFIG. 6. Also, the following relationship should exist:

(a c)/z1= 0.9 l.2

where:

a effective length of the short arm 80 c effective length of the link 78d distance between centerlines of throttle shafts l9 and 23.

FIGS. 7, 8 and 9 are diagrams showing how the primary throttle valve 18moves with respect to the secon dary throttle valve 20. In FIG. 7 boththrottle valves 18 and 20 are closed. When the terminal fitting 38 ofthe throttle cable 39 acts on the socket 37 to open the primary throttlevalve 18 about 40, as shown in FIG. 8, the secondary throttle valve 20remains closed because the cam roller 72a hasjust reached the camsurface 73 on the member 66. Continuing opening movement of theprimarythrottle 18 causes the roller 72a on the cam surface 73 to turnthe member 66 in a counterclockwise direction against the action of thetorsion spring 69. This moves the projection 67 away from the member 64so that the diaphragm assembly 75 may turn the throttle shaft 21 in acounterclockwise direction to open the secondary throttle valve 20. InFIG. 9 both throttle valves 18 and 20 are shown in open position.

As shown in FIG. 2, a crank arm 87 may be fixed to a projecting end ofthe shaft 19 for connection to a conventional accelerator pump, notshown.

In operation, initial cranking of the engine may require use of thechoke device 88. During this initial cranking the primary throttle valve18 and the auxiliary throttle valve 22 are in fast idle" position andthe sec ondary throttle valve 20 is closed. When the engine starts toturn under its own power and cranking is discontinued, the acceleratorpedal (not shown) is operated to move the throttle control cable 39 toturn the actuator member 25 in a clockwise direction as viewed inFIG. 1. This causes opening movement of the primary throttle valve 18and opening movement of the auxiliary throttle valve 22.

Initial movement of the actuator member 25 is resisted by the torsionspring 29, and after the member 25 turns a few degrees the rod 56bottoms out? within the device 57, preventing further turning movementof V the member 54. Further turning movement by the actuator member 25is resisted by both torsion springs 29 and 32.

When the primary throttle valve opens about 40 degrees, the cam surface62 has moved to permit the roller 63 and member 64 to turn about theaxis of the secondary throttle valve shaft 21. The heavy flow of airthrough the primary passage 12 produces a marked pressure drop in theventuri throat 15. A passage (not shown) connects this low pressure zonein the venturi to the vacuum-operated diaphragm assembly 75. Continuedopening movement of the primary throttle valve 18 by means of thethrottle control cable 39 causes an increase in speed of the engine withconsequent increase in volume of air drawn through the venturi throat15. This in turn produces a greater pressure depression at the venturithroat and causes the vacuuni-operated diaphragm assembly 75 to tensionthe rod 76 and thereby open the secondary throttle valve 20. Thissupplies additional quantities of lean mixture to the main combustionchambers of-the engine. At the same time the linkage 78, 80 and 82further increases the opening of the auxiliary throttle valve 22 toprovide an increase in the rate of delivery of the rich mixture to theauxiliary combustion chambers of the engine.

A control valve (not shown) connects the vacuumoperated diaphragmassembly 50 to manifold suction pressure only when the suction pressurereaches a predetermined magnitude, for example 530 mm of mer tle valve18 is moving toward closed position, because the vacuum intensity in thedevice 75 is not reduced quickly enough to respond to the changeinsuction pressure at the primary venturi throat 15. This difficulty isovercome by the action of the cam surface 62 and follower roller 63,which action forces closing of the secondary throttle valve astheprimary throttle valve 18 closes. Continual gradual deceleration causesfurther closing movement of the primary and secondary throttle valves,and the closing motion of the auxiliary throttle valve 22'is coordinatedwith the closing motion of the primary throttle valve 18.

If the operator of the vehicle rapidly lifts his foot away from theaccelerator pedal, rapid deceleration of the engine occurs because theprimary throttle valve 18 and the auxiliary throttle valve 22 movetoward idling position while the secondary throttle valve 20 movestoward closed position. The positioner assembly 50 acts to hold thethrottle valve open to a greater degree than its idle position duringdeceleration above a predetermined speed of the vehicle, to minimizeformation of unwanted emissions in the engine exhaust. The diaphragmassembly 57 first acts as a dash pot to limit too rapid closing of theprimary and auxiliary throttle valves, which might interfere with properoperation of the engine. It is desirable to reduce the closing rate ofthe primary throttle valve 18 as it approaches closed position, when thevehicle operator removes his foot from the accelerator pedal forshifting gears or for de celeration. This is necessary to overcome thefunction of the positioner assembly 50 which does not respond rapidlywhen the throttle valve 18 is rapidly approaching toward closedposition. Below about 12 miles per hour, a speed sensitive switch (notshown) interrupts the supply of vacuum pressure to the assembly 50, toallow closing of the primary throttle valve 18 to idle position. Thedevice 57 may also serve as a run-on preventer by venting its internalchamber to atmosphere when the electrical ignition circuit isde-energized.

In the modified form of the invention shown in FIGS. 10-13, thecarburetor assembly is employed for furnishing a lean mixture to each ofthe main combus tion chambers of the engine, and a second carburetorassembly 101 is provided for furnishing a rich mixture to the auxiliarycombustion chambers of the engine. The first carburetor assembly 100 isconventional in form and employs a throttle actuator bar 102 foroperating the throttle valves of the conventional carburetor assembly100. The throttle bar 102 is pivotally connected at 103 to the crankmember 104 secured to the intermediate shaft 105. A tension spring 106connects the crank member 104 to turn the shaft in a counterclockwisedirection, as viewed in FIG. 10. The auxiliary throttle valve 107 isfixed on the throttle shaft 108 mounted to turn on the body 109 of thecarburetor 101. A cam member 110 is fixed to a disk 111 secured to theshaft 105 and this cam 110 has a cam surface 112 engaged by a followerroller 113 on crank arm'1l4. The crank 115 connected to the throttleshaft 108 is adjustably connected to the crank. arm 114 by means of theadjusting screw 116. From this description it will be understood thatturning movement of the intermediate shaft 105 causes turning movementof the throttle valve 107 through the cam 110, follower roller 113, adjusting screw 116 and member 115.

The intermediate shaft 105 is supported in a bearing 118 fixed on thestationary bracket 119. The shaft 105 is also supported within the.stationary hollow hub 120 fixed to the stationary bracket 121. Anactuator mem ber 122 is mounted to turn on the hub 120 and is providedwith a socket 123 for reception of the end fitting 124 of the throttlecable 125. A tension spring 126 is connected to the actuator member 122to resist clockwise motion, as viewed in FIG. 11. A finger 132 on themember 104 projects over the actuator member 122 so that turningmovement of the actuator member 122 under force applied by the throttlecable 125 and against the action spring 126 serves to rotate the member104 to turn the intermediate shaft 105.

The diaphragm assembly 127 acts through rod 128 and pivotal connection129 to member 130 which is mounted to turn on the hollow stationary hub120. A finger 131 fixed to the disk 111 overlies a portion of the member130, so that tensioning of the rod 128 serves to turn the shaft 105 in aclockwise direction, as viewed in FIG. 10. This device may be referredto as a dash potv to prevent too rapid closing of the throttle valves.

The vacuum-operated diaphragm assembly 133 acts through rod 134 andpivotal connection 135 to turn the member, 136 which is mounted to turnon the stationary bearing 118. Another member 137 fixed to a projectingend of the shaft 105 has a finger 138 overlying a portion of the member136, so that tensioning of the rod 134 serves toturn the shaft 105. Thisdevice may be referred to as a throttle positioner.

It will be observed that the shaft 105 which is connected to turn theauxiliary throttle valve 108 is actuated from the throttle cable 125through a member mounted to turn on the stationary hub 120, and that theshaft 105 projects through the hub 120 so that the bending load causedby cable tension is taken by the stationary hub 120 and not by the shaft105. Also, it

will be observed that turning movement of the throttle 1 valve shaft 108is affected by the action of the diaphragm assembly 127, andvacuum-operated device 133, in addition to the action of the throttlecable 125.

In the further modified form of the invention shown in FIGS. 14 and 15,the conventional carburetor 100 is employed as before and its throttlevalves are operated by the throttle actuator bar 102. However, there isno intermediate shaft corresponding to shaft 105, and instead theauxiliary throttle valve shaft 140 is directly connected through member141 to members 142 and 143 which are mounted to turn on the stationaryhollow hub 144. This hub 144 is integrally formed with the body 145 ofthe auxiliary carburetor assembly 146. The auxiliary throttle valve 147is mounted in the passage 148 and serves to control the supply of richmixture to the auxiliary combustion chambers of the engine.

The throttle cable 150 has its end fitting 151 received in the socket152 mounted on the member 142. Tensioning of the throttle cable 150serves to turn the member 142 in a clockwise direction, as viewed inFIG.

mit the throttle valve 147 to open beyond a certain po-' sition withoutinterferencefrom the relatively short stroke rods 158 and 159.

The operation of the modified forms of the invention shown in FIGS.10-13 and 14-15 will be apparent from the foregoing description of thepreferred embodiment.

Having fully described our invention, it is to be understood that we arenot to be limited to the details set forth but that our invention is ofthe full scope of the appended claims.

We claim:

l. A carburetor assembly for use with an internal combustion enginehaving at least one main combustion chamber and an auxiliary combustionchamber connected thereto by a torch nozzle, said carburetor assemblyhaving, in combination: a primary passage adapted to supply a leanmixture to the main combustion chamber of the engine, an auxiliarypassage adapted to supply a rich mixture to the auxiliary com bustionchamber of the engine, each of the passages having a throttle valvetherein carried on a shaft, means mounting said shafts for turningmovement, said means including a hollow stationary hub encircling aportion of one of said shafts, a member mounted to turn on the hub,means for applying a linear force to said member to cause it to turn inone direction, resilient means connected to turn the member in the otherdirection, means on an end of the shaft projecting from the hubconnecting said member to turn said shaft, and means for coordinatingturning movements of said shafts.

2. The combination set forth in claim 1 in which said resilient meanscomprises a torsion spring encircling the hub.

3. The combination set forth in claim 1 in which the primary andauxiliary passages are both provided in a carburetor body, and whereinthe hollow stationary hub projects from the body.

4. The combination set forth in claim 1 in which the primary passage isformed in one body and the auxiliary passage is formed in another bodyspaced therefrom.

5. The combination set forth in claim 1 in which the latter said meansincludes adjusting means for changing the angular position of theauxiliary throttle valve with respect to the primary throttle valve.

6. The combination set forth in claim 1 in which the latter said meansincludes an arm connected to turn with each of said shafts,respectively, a link pivotally connected to each of said arms, and meansfor adjusting the angular position of one of the arms with respect toits respective shaft.

7. A carburetor assembly for use with an internal combustion enginehaving at least one main combustion chamber and an auxiliary combustionchamber connected thereto by a torch nozzle, said carburetor assemblyhaving, in combination: a body having a primary passage, a secondarypassage, and a auxiliary passage therein, the primary passage and thesecondary passage being adapted to supply a lean mixture to the maincombustion chamber of the engine, the auxiliary passage being adapted tosupply a rich mixture to the auxiliary combustion chamber of the engine,each of the passages havinga throttle valve therein and carried on ashaft, means mounting said shafts to turn on the body, said meansincluding a hollow stationary hub projecting from the body andencircling a portion of one of said shafts, a member mounted to turn onthe hub, means for applying a linear force to said member to cause it toturn in one direction, resilient means connected to turn the member inthe other direction, and means on an end of the shaft projecting fromthe hub connecting said member to turn saidshaft, and means forcoordinating turning movements of said shafts.

8. The combination set forth in claim 7 in which said resilient meanscomprises a torsion spring encircling said hub.

9. The combination set forth in claim 7 in which vacuum-operated meansare provided for turning the secondary throttle shaft, and cam andfollower means acting to permit movement of the secondary throttlesh'aft by said vacuum-operated means.

10. A carburetor assembly for use with an internal combustion enginehaving at least one main combustion chamber and an auxiliary combustionchamber connected thereto by a torch nozzle, said carburetor assemblyhaving, in combination: a primary passage and a secondary passageadapted to deliver a lean mixture to the main combustion chamber of theengine, an auxiliary passage adapted to deliver a rich mixture to theauxiliary combustion chamber of the engine, each of said passages havinga' throttle valve therein mounted on a throttle shaft, means mountingsaid throttle shafts for turning movement about parallel axes, a forwardextending arm connected to turn with the primary throttle shaft, arearward extending arm connected to turn with the auxiliary throttleshaft, a link pivotally connected to each of said arms to cause theprimary throttle valve and the auxiliary throttle valve to turn inopposite directions, and means including a cam and follower for causingturning movement of the secondary throttle valve after the main throttlevalve has turned through a predetermined arc of travel.

ll. The combination set forth in claim 10 in which angular adjustmentmeans are interposed between the rearward extending arm and theauxiliary throttle shaft.

12. A carburetor assembly for use with an internal combustion enginehaving at least one main combustion chamber and an auxiliary combustionchamber connected thereto by a torch nozzle, said carburetor assemblyhaving, in combination: a primary passage adapted to deliver a leanmixture of the main combustion chamber of the engine, an auxiliarypassage adapted to deliver a rich mixture to the auxiliary combustionchamber of the engine, each of said passages having a throttle valvetherein mounted on a throttle shaft, means mounting said throttle shaftsfor turning movement about parallel axes, a forward extending armconnected to turn with the primary throttle shaft, a rearward extendingarm connected to turn with the auxiliary throttle shaft, the effectivelength of the forward arm being approximately three-fourth ofthat of therearward arm, a link pivotally connected to each of said arms to causethe primary throttle valve and the auxiliary throttle valve to turn inopposite direction, the parts having the following geometricrelationship:

(a c)/d =09 1.2

rearward extending arm with respect to the auxiliary throttle valve.

14. The combination set forth in claim 12 in which the primary throttleshaft extends through a stationary hollow hub, an actuator membermounted to turn on the hub and carrying said forward arm, and meansconnecting the actuator member to the primary throttle shaft.

15. A carburetor assembly for use with an internal combustion enginehaving at least one main combustion chamber and an auxiliary combustionchamber connected thereto by a torch nozzle, said carburetor assemblyhaving, in combination: a primary passage and a secondary passageadapted to deliver a lean mixture of the main combustion chamber of theengine, an auxiliary passage adapted to deliver a rich mixture to theauxiliary combustion chamber of the engine, each of said passages havinga throttle valve therein mounted on a throttle shaft, means mountingsaid throttle shafts for turning movement about parallel axes, meansconnecting the main throttle valve and the auxiliary throttle valve forcoordinated turning movement, means for causing turning movement of thesecondary throttle valve after the main throttle valve has turnedthrough a'predetermined arc of travel, said means including vacuumoperated means for turning the secondary throttle valve, a springopposing the action of the vacuum operated means, and means including acam and follower acting to limit the extent of turning movement of thesecondary throttle shaft by said vacuum operated means.

16. A carburetor assembly for use with an internal combustion enginehaving at least one main combustion chamber and an auxiliary combustionchamber connected thereto by a torch nozzle, said carburetor assemblyhaving, in combination: a primary passage adapted to deliver a leanmixture to the main combustion chamber of the engine, an auxiliarypassage adapted to deliver a rich mixture to the auxiliary combustionchamber of the engine, each of said passages having a throttle valvetherein mounted on a throttle shaft, means mounting said throttle shaftsfor turning movement about parallel axes, a hollow stationary hub, amember mounted to turn on the hub, means for ap plying a force to saidmember to cause it to turn in one direction, resilient means connectedto turn the member in the other direction, means connecting said memberto turn one of said shafts, and means for coordinating turning movementsof said shafts.

17. The combination set forth in claim 16 in which said hollow hubmember receives the shaft for the auxiliary throttle valve.

18. The combination set forth in claim 16 in which said hollow hubmember receives an intermediate shaft positioned between said throttleshafts.

19. The combination set forth in claim 16 in which the latter said meansincludes adjusting means for changing the angular position of theauxiliary throttle valve with respect to the primary throttle valve,

20. A carburetor assembly for use with an internal combustion enginehaving at least one main combustion chamber and an auxiliary combustionchamber connected thereto by a torch nozzle, said carburetor assemblyhaving, in combination: a primary passage and a secondary passage eachadapted to deliver a lean mixture to the main combustion chamber of theengine, an auxiliary passage adapted to deliver a rich mixture to theauxiliary combustion chamber of the engine, each of said passages havinga throttle valve therein mounted on a throttle shaft, means mountingsaid throttle shafts for turning movement about parallel axes, saidmeans including two hollow stationary hubs, the first hub encircling aportion of the principal throttle shaft and the second hub encircling aportion of the secondary throttle shaft, a first member mounted to turnon the first huband having means for connection to a throttle actuator,means connecting said first member to the primary throttle shaft, asecond member mounted to turn on the second hub and connected to thesecondary throttle shaft, means for causing turning movement of thesecond member after said first member has turned through a predeterminedarc of travel, and means for coordinating turning movement of theprimary throttle shaft and the auxiliary throttle shaft.

21. The combination set forth in claim 20 in which the latter said meansincludes adjusting means for changing the angular position of theauxiliary throttle valve with respect to the primary throttle valve.

22. The combination set forth in claim 20 in which the means for causingturning movement of the second member includes a spring acting to turnthe second member, a cam on the first member and a follower on adaptedto supply a rich mixture to'the auxiliary combustion chamber of theengine, each of the passages having a throttle valve therein carried ona shaft, means mounting said shafts for turning movement, an actuatormember mounted to turn about the axis of the primary throttle shaft,means connecting said actuator member to said primary throttle shaft, afirst torsion spring resisting turning movement of said actuator memberin a direction to open said primary throttle valve, a second membermounted to turn about said axis, a second torsion spring operativelyinterposed between said actuator member and said second member, adash-pot device including a rod pivotally connected to said secondmember and acting to limit the rate of turning movement of said memberin a direction corresponding to closing movement of said throttle valve,said rod having a limited stroke, means whereby said second member mayturn the actuator member in the opposite direction until said rodreaches the limit of its stroke, whereby turning movement of theactuator member to open the primary throttle valve is first resistedonly by the first said torsion spring until said rod reaches the limitof its stroke and whereby continued turning movement of said actuator inthe same direction is resisted by both said torsion springs, and meansfor coordinating the movements of the primary throttle shaft and theauxiliary throttle shaft.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. 3,852,379

DATED December 3, 1974 lNV ENTOR(S) Toshimasa Shishido. et a1 It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In column 2, line 63, change "clockwise" to read counterclockwise-.

In column 3, line 45 "slot 10" should read slot 60----.

Signed and Sealed this Twenty-seventh Day Of July 1976 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (mnmissiuner ufParemsand Trademarks

1. A carburetor assembly for use with an internal combustion enginehaving at least one main combustion chamber and an auxiliary combustionchamber connected thereto by a torch nozzle, said carburetor assemblyhaving, in combination: a primary passage adapted to supply a leanmixture to the main combustion chamber of the engine, an auxiliarypassage adapted to supply a rich mixture to the auxiliary combustionchamber of the engine, each of the passages having a throttle valvetherein carried on a shaft, means mounting said shafts for turningmovement, said means including a hollow stationary hub encircling aportion of one of said shafts, a member mounted to turn on the hub,means for applying a linear force to said member to cause it to turn inone direction, resilient means connected to turn the member in the otherdirection, means on an end of the shaft projecting from the hubconnecting said member to turn said shaft, and means for coordinatingturning movements of said shafts.
 2. The combination set forth in claim1 in which said resilient means comprises a torsion spring encirclingthe hub.
 3. The combination set forth in claim 1 in which the primaryand auxiliary passages are both provided in a carburetor body, andwherein the hollow stationary hub projects from the body.
 4. Thecombination set forth in claim 1 in which the primary passage is formedin one body and the auxiliary passage is formed in another body spacedtherefrom.
 5. The combination set forth in claim 1 in which the lattersaid means includes adjusting means for changing the angular position ofthe auxiliary throttle valve with respect to the primary throttle valve.6. The combination set forth in claim 1 in which the latter said meansincludes an arm connected to turn with each of said shafts,respectively, a link pivotally connected to each of said arms, and meansfor adjusting the angular position of one of the arms with respect toits respective shaft.
 7. A carburetor assembly for use with an internalcombustion engine having at least one main combustion chamber and anauxiliary combustion chamber connected thereto by a torch nozzle, saidcarburetor assembly having, in combination: a body having a primarypassaGe, a secondary passage, and a auxiliary passage therein, theprimary passage and the secondary passage being adapted to supply a leanmixture to the main combustion chamber of the engine, the auxiliarypassage being adapted to supply a rich mixture to the auxiliarycombustion chamber of the engine, each of the passages having a throttlevalve therein and carried on a shaft, means mounting said shafts to turnon the body, said means including a hollow stationary hub projectingfrom the body and encircling a portion of one of said shafts, a membermounted to turn on the hub, means for applying a linear force to saidmember to cause it to turn in one direction, resilient means connectedto turn the member in the other direction, and means on an end of theshaft projecting from the hub connecting said member to turn said shaft,and means for coordinating turning movements of said shafts.
 8. Thecombination set forth in claim 7 in which said resilient means comprisesa torsion spring encircling said hub.
 9. The combination set forth inclaim 7 in which vacuum-operated means are provided for turning thesecondary throttle shaft, and cam and follower means acting to permitmovement of the secondary throttle shaft by said vacuum-operated means.10. A carburetor assembly for use with an internal combustion enginehaving at least one main combustion chamber and an auxiliary combustionchamber connected thereto by a torch nozzle, said carburetor assemblyhaving, in combination: a primary passage and a secondary passageadapted to deliver a lean mixture to the main combustion chamber of theengine, an auxiliary passage adapted to deliver a rich mixture to theauxiliary combustion chamber of the engine, each of said passages havinga throttle valve therein mounted on a throttle shaft, means mountingsaid throttle shafts for turning movement about parallel axes, a forwardextending arm connected to turn with the primary throttle shaft, arearward extending arm connected to turn with the auxiliary throttleshaft, a link pivotally connected to each of said arms to cause theprimary throttle valve and the auxiliary throttle valve to turn inopposite directions, and means including a cam and follower for causingturning movement of the secondary throttle valve after the main throttlevalve has turned through a predetermined arc of travel.
 11. Thecombination set forth in claim 10 in which angular adjustment means areinterposed between the rearward extending arm and the auxiliary throttleshaft.
 12. A carburetor assembly for use with an internal combustionengine having at least one main combustion chamber and an auxiliarycombustion chamber connected thereto by a torch nozzle, said carburetorassembly having, in combination: a primary passage adapted to deliver alean mixture of the main combustion chamber of the engine, an auxiliarypassage adapted to deliver a rich mixture to the auxiliary combustionchamber of the engine, each of said passages having a throttle valvetherein mounted on a throttle shaft, means mounting said throttle shaftsfor turning movement about parallel axes, a forward extending armconnected to turn with the primary throttle shaft, a rearward extendingarm connected to turn with the auxiliary throttle shaft, the effectivelength of the forward arm being approximately three-fourth of that ofthe rearward arm, a link pivotally connected to each of said arms tocause the primary throttle valve and the auxiliary throttle valve toturn in opposite direction, the parts having the following geometricrelationship: (a + c)/d 0.9 -1.2 where: a effective length of forwardarm c effective length of the link d distance between centerlines ofthrottle shafts.
 13. The combination set forth in claim 12 in whichmeans are provided for adjusting the position of the rearward extendingarm with respect to the auxiliary throttle valve.
 14. The combinationset forth in claim 12 in which the primary throttle shaft extendsthrough a stationary hollow hub, an actuator member mounted to turn onthe hub and carrying said forward arm, and means connecting the actuatormember to the primary throttle shaft.
 15. A carburetor assembly for usewith an internal combustion engine having at least one main combustionchamber and an auxiliary combustion chamber connected thereto by a torchnozzle, said carburetor assembly having, in combination: a primarypassage and a secondary passage adapted to deliver a lean mixture of themain combustion chamber of the engine, an auxiliary passage adapted todeliver a rich mixture to the auxiliary combustion chamber of theengine, each of said passages having a throttle valve therein mounted ona throttle shaft, means mounting said throttle shafts for turningmovement about parallel axes, means connecting the main throttle valveand the auxiliary throttle valve for coordinated turning movement, meansfor causing turning movement of the secondary throttle valve after themain throttle valve has turned through a predetermined arc of travel,said means including vacuum operated means for turning the secondarythrottle valve, a spring opposing the action of the vacuum operatedmeans, and means including a cam and follower acting to limit the extentof turning movement of the secondary throttle shaft by said vacuumoperated means.
 16. A carburetor assembly for use with an internalcombustion engine having at least one main combustion chamber and anauxiliary combustion chamber connected thereto by a torch nozzle, saidcarburetor assembly having, in combination: a primary passage adapted todeliver a lean mixture to the main combustion chamber of the engine, anauxiliary passage adapted to deliver a rich mixture to the auxiliarycombustion chamber of the engine, each of said passages having athrottle valve therein mounted on a throttle shaft, means mounting saidthrottle shafts for turning movement about parallel axes, a hollowstationary hub, a member mounted to turn on the hub, means for applyinga force to said member to cause it to turn in one direction, resilientmeans connected to turn the member in the other direction, meansconnecting said member to turn one of said shafts, and means forcoordinating turning movements of said shafts.
 17. The combination setforth in claim 16 in which said hollow hub member receives the shaft forthe auxiliary throttle valve.
 18. The combination set forth in claim 16in which said hollow hub member receives an intermediate shaftpositioned between said throttle shafts.
 19. The combination set forthin claim 16 in which the latter said means includes adjusting means forchanging the angular position of the auxiliary throttle valve withrespect to the primary throttle valve.
 20. A carburetor assembly for usewith an internal combustion engine having at least one main combustionchamber and an auxiliary combustion chamber connected thereto by a torchnozzle, said carburetor assembly having, in combination: a primarypassage and a secondary passage each adapted to deliver a lean mixtureto the main combustion chamber of the engine, an auxiliary passageadapted to deliver a rich mixture to the auxiliary combustion chamber ofthe engine, each of said passages having a throttle valve thereinmounted on a throttle shaft, means mounting said throttle shafts forturning movement about parallel axes, said means including two hollowstationary hubs, the first hub encircling a portion of the principalthrottle shaft and the second hub encircling a portion of the secondarythrottle shaft, a first member mounted to turn on the first hub andhaving means for connection to a throttle actuator, means connectingsaid first member to the primary throttle shaft, a second member mountedto turn on the second hub and connected to the secondary throttle shaft,means for causing turning movement of the second member after said firstmember has turned through a predetermined arc of travel, and Means forcoordinating turning movement of the primary throttle shaft and theauxiliary throttle shaft.
 21. The combination set forth in claim 20 inwhich the latter said means includes adjusting means for changing theangular position of the auxiliary throttle valve with respect to theprimary throttle valve.
 22. The combination set forth in claim 20 inwhich the means for causing turning movement of the second memberincludes a spring acting to turn the second member, a cam on the firstmember and a follower on the second member for limiting motion of thesecond member under force applied by the spring.
 23. A carburetorassembly for use with an internal combustion engine having at least onemain combustion chamber and an auxiliary combustion chamber connectedthereto by a torch nozzle, said carburetor assembly having, incombination: a primary passage adapted to supply a lean mixture to themain combustion chamber of the engine, an auxiliary passage adapted tosupply a rich mixture to the auxiliary combustion chamber of the engine,each of the passages having a throttle valve therein carried on a shaft,means mounting said shafts for turning movement, an actuator membermounted to turn about the axis of the primary throttle shaft, meansconnecting said actuator member to said primary throttle shaft, a firsttorsion spring resisting turning movement of said actuator member in adirection to open said primary throttle valve, a second member mountedto turn about said axis, a second torsion spring operatively interposedbetween said actuator member and said second member, a dash-pot deviceincluding a rod pivotally connected to said second member and acting tolimit the rate of turning movement of said member in a directioncorresponding to closing movement of said throttle valve, said rodhaving a limited stroke, means whereby said second member may turn theactuator member in the opposite direction until said rod reaches thelimit of its stroke, whereby turning movement of the actuator member toopen the primary throttle valve is first resisted only by the first saidtorsion spring until said rod reaches the limit of its stroke andwhereby continued turning movement of said actuator in the samedirection is resisted by both said torsion springs, and means forcoordinating the movements of the primary throttle shaft and theauxiliary throttle shaft.